With the continuous increase of the integration degree of semiconductor devices on a chip, the critical dimensions of the transistors are steadily reduced. The reduction of critical dimensions means that more transistors can be arranged on the chip. However, the rapid decrease in the dimension of the transistors challenges performance of the transistors.
Among switch-mode power-supply devices with an intermediate/high power, insulated gate bipolar transistor (IGBT) has been increasingly applied to the modern electric and electronic technology because of the characteristics that IGBT demonstrates, such as simple control/driving circuit, high operation frequency, large capacity, etc.
An IGBT is a composite device combining a metal-oxide-semiconductor field-effect transistor (MOSFET) and a bipolar transistor. Specifically, the input terminal of an IGBT is associated with a MOSFET, and the output terminal is associated with a PNP transistor. Therefore, the IGBT may be regarded as a Darlington tube with a MOS input. Accordingly, the IGBT may have the advantages of both transistors. That is, the IGBT may not only demonstrate advanced features of the MOSFET device such as high input impedance, simple and rapid driving characteristics, etc., but also demonstrates advanced features of bipolar transistors such as low conduction voltage drop, large capacity, etc.
However, the IGBTs formed by existing fabrication methods often face problems such as long turn-off trailing time, high turn-off energy consumption, etc. The disclosed IGBTs and fabrication methods are directed to solve one or more problems set forth above and other problems in the art.